Flexible circuit boards are commonly used in compact mobile electronic and telecommunications devices including, but not limited to, cell phones, cameras, handheld computers, MP3 players, global positioning system (GPS) mapping devices, implantable medical devices, and the like, in which efficient use of space inside a device package, or housing, is a feature of critical importance. A typical sequence of steps for manufacturing such mobile devices includes populating a planar flexible substrate with electronic components by mounting components on both sides of the substrate, folding the planar circuit into a desired three-dimensional configuration, and then placing the three-dimensional folded circuit inside the device package, which may be outfitted with a supporting device frame. The planar flexible substrate may be formed into a regular or an irregular shape, and it may include tabs or extensions that, when folded, conform to the interior shape of the housing or that accommodate other parts contained within the housing, such as, for example, batteries, telemetry units, and digital memory chips. Flexible substrates are often made of polyimide or a similar type of polymer that may comprise a multi-layer laminate.
A circuit folding assembly operation typically involves the use of a complex, customized fixture, such as, for example, a specialized jig for holding and supporting the flexible substrate during a mechanized bending process, so as to avoid creasing the substrate, rupturing interconnecting wires, subjecting the substrate or components mounted thereon to high stresses during folding, or otherwise damaging the substrate and/or components. An exemplary multi-step bending process that relies on such equipment is described in a published white paper by Shereen Lim from Avago Technologies, entitled “Recommendations for Installing Flash LEDs on Flex Circuits”. Often, adhesive or mechanical fixation is required to maintain the final, folded, three-dimensional configuration. Customized supporting accessories such as, for example, rigidizer plates, pallets, mandrels, clamps, and the like, are also commonly used to assist in the bending process, as described in U.S. Pat. No. 5,434,362 to Klosowiak, et al., entitled “Flexible Circuit Board Assembly and Method”. Such tools increase manufacturing costs and complexity, because a new jig and accompanying accessories must be designed and constructed for each new folded circuit configuration. Often, operator intervention is also necessary during folding, which may include a series of multiple bends and/or multiple manual fixation steps. After the bending process is complete, the folded circuit must be aligned with the supporting frame, manually held in place so as not to disturb the folded shape, and then carefully inserted into the housing.
The presently disclosed invention is directed toward overcoming one or more of the above-identified problems.